Brown fat is one of two types of adipose tissue found in the human body. During embryogenesis, brown fat is derived from the differentiation of the mesoderm. Brown fat is involved in development and homeostasis by providing metabolic tissue capable of providing heat. Brown fat helps regulate metabolism and nonshivering thermogenesis. In addition, brown fat plays a larger role than white adipose tissue in regulating metabolism. Brown fat makes up 5 percent of the body mass of a human neonate, and less than 1 percent of the body mass of an adult.
Metabolic activity of brown fat decreases with increased body mass index. Similarly, metabolic activity of brown fat decreases with increased body fat percent.
Stem cells have been identified and isolated in various tissues, and white adipose tissue stem cells have been isolated, expanded and shown to have functional therapeutic characteristics. To date, no stem cell population population has been identified in brown adipose tissue.